2.6 Carbohydrates

Introduction

Carbohydrates are one of the four fundamental biological molecules. They are the compounds of carbon, hydrogen, and oxygen. They are commonly known as sugars or saccharides. They are the primary source of energy for living organisms and also play important structural roles.

Definition

Carbohydrates: Carbohydrates are organic biomolecules or their derivatives in which all the carbon atoms are hydrated, having the generalized formula:

C_n(H₂O)_n

where n is the number of carbon atoms and the number of water molecules.

In simple words: Carbohydrates are molecules made of carbon, hydrogen, and oxygen, where hydrogen and oxygen are in the same ratio as in water (2:1).

Core Concept

• Literally, the word carbohydrate means "hydrates of carbon" — a carbon associated with water.
• According to this classic concept, carbohydrates are organic biomolecules or their derivatives in which all the carbon atoms are hydrated.
• The general formula is C_n(H₂O)_n.
• For example, glucose has the molecular formula:
• However, this formula is not exactly applicable in some cases. For example:
• Lactic acid: C₃H₆O₃
• Acetic acid: C₂H₄O₂

Detailed Explanation

Chemical Nature of Carbohydrates

• Carbohydrates are compounds of carbon, hydrogen, and oxygen.
• The name "carbohydrate" comes from the idea that these molecules are hydrates of carbon — carbon combined with water.
• The general formula is C_n(H₂O)_n.
• However, not all carbohydrates fit this formula exactly.
• Some carbohydrates also contain nitrogen, sulphur, or phosphorus (e.g., chitin contains nitrogen).

Examples of Carbohydrates